Ion Mobility DMS Modifiers for Signal Loss and Resolution
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Solution Overview
Problem
Differential Mobility Spectrometers (DMS) face sensitivity reductions when interfaced with Mass Spectrometers (MS), particularly due to diffusion losses, ion clustering, and inefficiencies in ion transport, especially at high solvent flows, which limits the detection limit and applicability of DMS-type analyses.
Innovation Solution
Introducing a mixture of two or more liquid modifiers into the drift gas stream, where one solvent improves separation capability and another with higher proton solvation energy suppresses proton transfer and analyte dissociation, and optionally including an arcing suppressant modifier to enhance sensitivity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If liquid modifiers are introduced to improve separation capability, then ion separation performance is improved, but signal intensity is reduced
Solution Approach 1:
The patent introduces a multi-component modifier system where each component acts as an intermediary with specific functions: the first modifier (e.g., hexanol) enhances separation by clustering with ions, the second modifier (e.g., methanol) suppresses proton transfer and analyte dissociation, and the third modifier (e.g., chloroform) prevents electrical discharges. This coordinated intermediary system resolves the contradiction by distributing functions across multiple agents rather than relying on a single modifier that would compromise signal intensity.
Solution Approach 2:
The patent employs a composite modifier mixture comprising multiple liquid modifiers in specific proportions rather than a single pure compound. This composite approach allows the system to simultaneously achieve ion clustering for separation, proton transfer suppression, and electrical discharge prevention, thereby maintaining signal intensity while improving separation capability through the synergistic effects of the modifier components.
2Productivity
If high solvent flows are used to improve ion transport, then analysis throughput is improved, but ion clustering and diffusion losses increase
Solution Approach 1:
The patent converts the harmful effect of high solvent flow-induced ion clustering into a beneficial separation mechanism. By introducing modifiers that promote controlled ion clustering, the system transforms what would normally be a source of signal loss into a mechanism for enhanced ion separation and detection, allowing high flow rates to be maintained while actually improving analytical performance through the modified clustering behavior.
3Measurement precision
If separation voltage is increased to improve resolution, then ion separation resolution is improved, but electrical discharges occur
Solution Approach 1:
The patent introduces an arc-suppressing modifier (e.g., chloroform) as an intermediary substance that prevents electrical discharges at high separation voltages. This modifier acts as a protective intermediary between the high voltage field and the gas medium, allowing the system to operate at elevated voltages for improved resolution without suffering from electrical discharge events that would normally limit the maximum usable voltage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach restores signal intensity and improves sensitivity and selectivity in DMS-MS systems, allowing for higher separation voltages and increased resolution, particularly at higher solvent flows, thereby expanding the range of analytes that can be detected with improved detection limits.
Implementation Method 1
a DMS/FAIMS/IMS separates and analyzes ions based on the mobility characteristics of the ions
Implementation Method 2
ions are pulsed into and pass through a drift tube while being subjected to a constant electric field
Implementation Method 3
The ions interact with a drift gas in the drift tube and the interactions affect the time it takes for the sample ions to pass through the drift tube
Implementation Method 4
another with higher proton solvation energy suppresses proton transfer and analyte dissociation
Implementation Method 5
uses an asymmetric electric field waveform that is applied between at least two parallel electrodes through which the ions pass
Implementation Method 6
an asymmetric voltage waveform that can be applied to generate an asymmetric electric field... The ion's mobility in the asymmetric electric field indicates a net movement
Data Source
AI summary
A method and system for performing an ion mobility based analysis that ionizes the components of a sample into ions; provides a field asymmetric waveform ion mobility or differential mobility spectrometry ion mobility based filter that comprises at least two electrodes, the at least two electrodes being spaced apart such that a constant sized gap is formed there between, through which a drift gas flows; introducing said ions into the drift gas, wherein said drift gas also comprises a mixture of liquid modifiers.